The new space movement has seen a rise since the last decade, thanks to CubeSats, which are affordable with fast development times and ease of deployment. One of the major subsystems in a CubeSat is the Electrical Power System (EPS), which generates, stores, and distributes electrical power to various subsystems of CubeSats. The first step in ensuring a productive CubeSat mission is to choose an efficient EPS design. This article’s primary goal is to provide a comprehensive review of all traditional and evolving CubeSat EPS systems. EPS designs have been divided into four types, and the operational elements of these architectures as well as a qualitative comparison have been provided. In addition, in this comprehensive review, CubeSat’s EPS is presented with some prospective research areas for future research work and invention.